Memphis Posted September 1, 2013 Report Share Posted September 1, 2013 Hi I've tried to control an intake fan and a extraction fan by using SET AND RESET Coils, controlled by a set point (saved as a HMI entry MI). I also included a timer subroutine to try and prevent relay bounce However the program does not reset the coil when the temperature lowers. This is the Fan section of the project (the 1st image), showing the 'SET' part of the ladder This is the 'RESET' net Both the set and reset ladders also have a touch controlled on/off switch represented by positive/negative transitional This image shows the timer net, that is meant to stop relay bounce It should i think in theory work, if there are any experienced coders that would like to take a look that would be marvellous Thanks Memphis Quote Link to comment Share on other sites More sharing options...
Emil Posted September 1, 2013 Report Share Posted September 1, 2013 Instead timer, maybe you can try ot set a little hysteresis. Please check the example ON-off control in VisiLogic. I'll divide the conditions to start and stop the fan for both temperature and humidity setpoints and they both will operate bits. Then will OR these bits to activate the real output. This seems to me easy for edit and debug. Quote Link to comment Share on other sites More sharing options...
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